I'm new to the Rails ecosystem but from what I've seen and also with many years using Django (which is very similar), I would agree with your assessment regarding Rails. The complex monolith that speeds up development very much has its place, especially at the beginning of a project. You can always cut it apart later as needed.

Regarding Node.js, however, I would say the pain is not worth it. For the same purpose I would now reach for Go (for networking stuff) or Rust (for high performance). This is after several years in a Node shop.